BIG PHYSICS, BIG QUESTIONS –

Double blasts may have birthed exotic quark stars

FORGET supernovae. Something more exotic and elusive may have been spotted – quark-novae.

When a very massive star runs out of fuel, it can explode in a supernova. The blast sometimes leaves a dense stellar remnant made mostly of neutrons.

But neutrons are made of even smaller particles called quarks. In theory, the core of a neutron star can get dense enough to undergo an additional explosive transition to create a star made mostly of quarks. Such an object would offer clues to how matter behaves at extremely high densities.

Rachid Ouyed of the University of Calgary in Alberta, Canada, and colleagues say the best evidence yet for quark stars lies with blasts called SN 2009ip and SN 2010mc. Both had two brightness peaks, unusual for supernovae. Intriguingly, SN 2009ip was labelled a supernova imposter because it flared up periodically, before finally exploding in a double-peaked burst.

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Ouyed and colleagues instead think the first peak in both events was a normal supernova (arxiv.org abs/1308.3927v1). The blasts left massive, rapidly spinning neutron stars, which, as their spin slowed, got so dense that their neutrons became quarks, triggering quark-novae.

This article appeared in print under the headline “Double bangs may be quark star births”